Document WO 2008/115899 A2 describes a compact and portable optical shaving device which cuts hair shafts using electromagnetic radiation. According to a preferred embodiment, the optical shaving device includes a power source that connects to one or more optical components. An optical device, such as an optical blade, can connect to and aligns with the array of optical components. The optical component(s) can provide light to the optics based on electrical energy from the power source. The optical component(s) or the optics can manipulate and direct the electromagnetic radiation to cut the hair shafts.
Classical shaving methods used commonly for the removal of facial and/or body hair employ certain selection means adapted for ensuring selective removal of hair whilst avoiding the potential risk of skin damage. For typical electrical shaving means, such as the common foil and rotating shaving systems, the selection means comprises a mechanical filter through which hairs can substantially penetrate and enter into the cutting chamber while skin is not able to substantially penetrate, avoiding excessive skin damage and irritation. In a rotating shaver, manipulation is preferably done by the shaving head and the cutting is preferably done by the knife. For blade shavers the selection means commonly comprise a mechanical arrangement with a combination of skin stretcher and gliding strip that limits the amount of skin exposure to the blade, while a spring system behind the knife effectively limits the local blade-skin interaction force to avoid cutting the skin. The means adapted for hair-skin selectivity comprised by the cutting mechanism actively limit the potential closeness of the shaving technique in order to balance the amount of acceptable skin irritation.
Conventional electrical shaving systems limit either the proximity of the cutting element to the skin, such as rotating/foil shavers, or limit the amount of force the blade exerts on the skin, such as blade shavers, in order to avoid accidental cutting of skin and skin irritation, nicks and cuts. The shaving process by these conventional shaving techniques typically comprises some or all of the following sub-processes: skin pre-treatment, skin manipulation, hair manipulation, hair refraction, hair cutting and skin post-treatment. There are many process variables that influence the desired outcome, these are amongst others: environmental conditions, such as humidity and temperature; device handling, such as speed, time, accuracy and pressure; device contour following capabilities and hair/skin properties.
The way in which each of the conventional shaving methods balances closeness and irritation depends strongly on its specific characteristics. In system blade shavers a number of sequentially passing blades each retract while cutting the hair, i.e. the blades pull the hair while cutting it. The next blade is then capable of cutting the hair at an even lower level, resulting in superior closeness. For rotating shaving, closeness is obtained through a combination of hair manipulation and hair retraction, together resulting in reasonable closeness. Foil shavers, lacking a clear means for hair refraction, rely mostly on a thin foil combined with skin and hair manipulation in order to achieve closeness.
For each of the methods described the amount of manipulation is limited due to the limitations imposed by the desire to maintain the integrity of the skin and to preserve the comfort during the shaving process. For instance, for blade shavers it is important to limit the amount of force required for hair cutting since otherwise the hair-pulling effect becomes highly uncomfortable, even though it might lead to improved closeness. For significant skin manipulation in, for instance, a foil or rotating shaving system, a high amount of local skin pressure is required which would result in extreme requirements for the force exerted by the device, and, hence, by the user on her/his skin, which would lead to excessive skin doming through holes and slots into the cutting chamber, resulting in skin irritation. The retraction means of rotating shaving systems is limited on account of the required acceleration of the hairs which is in the order of 1000 g and by the probability of correctly catching and retracting each hair.
However, a problem associated with each of the aforementioned techniques is that the processes of manipulation of hair and skin are performed with commonly the same means that are used to eventually cut the hairs, thus significantly limiting the amount of manipulation that can be employed, making the manipulation techniques sub-optimal. In addition, in each of the methods mentioned, the cutting process is non-optional, i.e. if an object is presented in front of a blade or inside the cutting chamber it will be cut, irrespective of whether it is actually being manipulated properly or whether it is a hair at all.